We propose an internship, and subsequent thesis, aimed at studying the opto-electronic consequences of nanoscale disorder in nitride semiconductor heterostructures used in lighting applications. To do so, the candidate may use novel experiment tools developed at Ecole polytechnique, including scanning tunnelling luminescence microscopy which combines the spatial resolution of STM with the spectral resolution of optical spectroscopy, low energy photo-emission and high resolution photoluminescence and photoluminescence excitation spectroscopy. These tools are unique in that they are used to study fundamental physical processes affecting electron dynamics in operational devices, including commercial light-emitting diodes. As such, our goal is to provide physical insights that will help to design the high efficiency light emitters of tomorrow.